Method of Making Triglyceride Macromonomers

ABSTRACT

A method of making a polymerisable ethylenically unsaturated macromonomer comprising the steps of: i) providing a chosen unsaturated non-mineral oil or a mixture of unsaturated non-mineral oils having a first blend of triglycerides, ii) treating the mixture of oils with a transesterification catalyst to produce a second blend of triglycerides different to the first, iii) reacting the second blend of triglycerides with an enophile having an acid, ester or anhydride moiety to form an adduct, iv) reacting the adduct with an ethylencially unsaturated monomer having a moiety reactive with the acid, ester or anhydride moiety of the enophile to form an intermediate, v) reacting the intermediate of step (iv) with a chain extender having at least two moieties reactive with the acid, ester or anhydride moiety of the enophile to form the ethylenically unsaturated macromonomer.

This invention relates to a method of making ethylenically unsaturatedmacromonomers derived from transesterified unsaturated non-mineraloils-especially plant and vegetable oils; to the macromonomers;polymers-particularly in the form of aqueous dispersions derived fromthem and finally adhesives, coatings, especially architectural coatings,comprising the polymers.

By architectural coatings is meant paints, varnishes and woodstains,especially for use on the interior and exterior of structures andbuildings such as houses, and also coatings for use in the garden suchas fence paints and also metal used on railings.

There is increasing awareness of the need to use renewable resources inindustry.

For many years, the main feedstock for industry, especially the chemicalindustry, has been fossil feedstock, either in the form of petroleum orcoal. Whilst economists, mining and oil exploration experts may argueabout the lifetime of known and yet to be discovered fossil feedstockreserves, it is indisputable that, in time, those reserves willinevitably be exhausted and even prior to that, become too expensive tobe of any use as a feedstock in all but the most specialisedapplications.

Furthermore, converting this fossil feedstock into useful material forindustry requires energy, releasing carbon dioxide and contributing toglobal warming. In addition, at the end of the useful life of thematerial, still more carbon dioxide is released, further adding toglobal warming.

Coatings typically comprise a mixture of particulate inorganic materialand organic material. The inorganic material is usually a mixture ofpigments and fillers and/or extenders. The pigments give colour to thepaint and the fillers and extenders provide other properties, such ashardness, to the paint film. The organic material largely comprises abinder, the role of which, as the name suggests, is to bind anyparticulate matter together. It also provides adhesion to the surface towhich the coating is applied.

The binders are usually high molecular weight polymers derived frommonomers obtained by refining and further processing of fossilfeedstock. The polymers are often produced in the form of aqueousdispersions of polymer microparticles referred to as latex. Forsimplicity it should be understood that the term polymer is used here toinclude homopolymers, copolymers, terpolymers and so on.

The manufacture and use of such polymer binders consumes some of theworlds non-renewable resources and in the process produces carbondioxide.

Thus there is a need for polymer binders that are based, at least inpart, on renewable feedstock such as that obtained from plant and/oranimal material.

Oils are such a natural and renewable feedstock obtainable from variousplants and animals, including fish. In the case of plants, it isgenerally the fruit that yields the oil. The term oil as used here,excludes mineral oils obtained form fossil feedstock such as petroleumand coal.

These oils are largely composed of a mixture of triglycerides (ietri-esters of glycerol) characterised by the fatty acids portion. Forexample, the fatty acids component of the triglycerides making up palmoil, linseed oil and soya oil are shown below and have the followingapproximate composition by weight %:

Palm oil Linseed oil Soya oil Palmitic acid (C₁₆, 0) 44 6 10 Stearicacid (C₁₈, 0) 4.5 2.5 4 Arachidic (C₂₀, 0) 0 0.5 0 Oleic acid (C₁₈, 1)40 19 23 Linoleic (C₁₈, 2) 10 24.1 51 Linolenic (C₁₈, 3) 0 47.4 7 Other1.5 0.5 5 Saturated 48.5 9 14 Unsaturated (total) 50.0 90.5 81Unsaturated (>1) 10.0 71.5 58 Iodine value 44-54 155-205 120-141

The subscript refers to the carbon chain length of the fatty acid and 0,1 or 2 indicates the number of ethylenically unsaturated bonds in thefatty acid.

Such unsaturated oils can be classified as drying, non-drying orsemi-drying oils. What is meant by such terminology is the extent towhich they autoxidise at normal temperatures to form a hard, dry film.Autoxidation is the process by which unsaturated oils absorb oxygen fromthe atmosphere to form in-situ hydroperoxides which then decompose toproduce free radicals causing the oils to dry. The more unsaturatedbonds the oil has, the more rapidly and completely it will dry.Similarly, oils with at least two unsaturated bonds per triglyceride,especially when conjugated, autoxidise even more readily. Nature,however, rarely produces conjugated unsaturation.

The extent of the unsaturation is measured by the iodine value. It isgenerally regarded that non-drying oils have iodine values of less than100, semi-drying oils from 100 to 140 and drying oils over 140 g ofiodine per 100 g of oil. A more extensive list of iodine values can befound on pages 34 and 35 of The Chemistry of Organic Film Formers by D.H. Solomon, published by John Wiley and Sons in 1967, which are herebyincorporated by reference.

The oils can be characterised according to the number of double bondsper triglyceride type. We have found that a typical sample of palm oil,for example, has the following distribution, expressed on a weight %basis.

5 double bonds per triglyceride <1

4 double bonds per triglyceride ca 10

3 double bonds per triglyceride ca 5 to 10

2 double bonds per triglyceride ca 35

1 double bonds per triglyceride ca 35 to 40

0 double bonds per triglyceride ca 10

Thus whilst approximately 48.5% of the fatty acids in the oil arepalmitic or stearic and thus saturated, nevertheless only about 10% ofthe triglycerides will be composed of fatty acids where all three aresaturated, and therefore free of double bonds. This saturated portion ofthe palm oil is unreactive to enophile and dienophiles.

U.S. 20050203246 discloses monomer formed by reacting unsaturatedvegetable oils (specifically sunflower oil, linseed oil or soya beanoil) with an enophile or dienophile having an acid, ester or anhydridefunctionality, to form a derivative followed by reacting the derivativewith a suitable hydroxyl, amine, thiol, oxirane or other functionalvinyl monomer to form an ethylenically unsaturated triglyceride monomer.The weight average molecular weight of such monomers is approximately1000 Daltons. It also discloses polymer latices containing up to 6% byweight of the monomer calculated on the polymer solids

However, we have found that dried films of latices derived from monomermixtures comprising such triglyceride monomer, and paints based on them,tend to be soft. They also tend to exude oily material, which appears onthe surface, over time.

In addition, architectural coatings using binders comprising suchmonomers, especially those used on interior surfaces, tend to have ayellow hue. This makes it difficult to formulate bright whites and thepastel colours.

There are further problems with the prior art. Being natural products,the composition of the oils varies significantly from year to year, thegeographic location of the source and the degree of any furtherprocessing that may be carried out on the oil. Blending oils fromdifferent sources and even of different types not only produce a moreconsistent feedstock, but also enables oils having a triglyceridecomposition not found in nature to be produced.

However, even such blends are not ideal, because they consist of acomplex mixture of triglycerides having saturated and mono andpoly-unsaturated fatty acid portions. This inevitably results in adistribution of species being formed when the oils are subsequentlyreacted with polyfunctional material.

These problems of the known prior art severely limits the utility ofthese known triglyceride monomers made by known methods.

We have now developed a new method of making macromonomer based onunsaturated non-mineral oils obtained from transesterified plant oranimal material which can be used in much higher amounts in polymerbinders which overcome the aforementioned problems.

According to the present invention there is provided a method of makinga polymerisable ethylenically unsaturated macromonomer comprising thesteps of

i) providing a chosen unsaturated non-mineral oil or mixture ofunsaturated non-mineral oils having a first blend of triglycerides

ii) treating the mixture of oils with a transesterification catalyst toproduce a second blend of triglycerides different to the first

iii) reacting the second blend of triglycerides with an enophile havingan acid, ester or anhydride moiety to form an adduct

iv)reacting the adduct with an ethylencially unsaturated monomer havinga moiety reactive with the acid, ester or anhydride moiety of theenophile to form an intermediate

v)reacting the intermediate of step iv) with a chain extender having atleast two moieties reactive with the acid, ester or anhydride moiety ofthe enophile to form the ethylenically unsaturated macromonomer.

The macromonomer is considered to be polymerisable through the ethylenicunsaturation provided by the monomer in step iv) rather than through anyunreacted unsaturation in the fatty acid chains of the triglyceridescomprising the oil. Normally, the polymerisable ethylenic unsaturationof the macromonomer is dependent from the fatty acid chain, usuallyindirectly, rather than exists in the backbone of the chain.

Preferably the weight average molecular weight, Mw, of the macromonomeris 1000 to 50000 Daltons, more preferably from 1500 to 40000, still morepreferably from 2000 to 40000, yet more preferably from 5000 to 30000Daltons, even more preferably from 10000 to 25000 Daltons and mostpreferably form 19000 to 23000 Daltons. The number average molecular, Mnis preferably from 1000 to 5000 Daltons, more preferably from 1000 to4000, even more preferably from 1000 to 3000 and most preferably from1500 to 3000 Daltons.

For simplicity, the term enophile is used to include dienophile.

Enophiles have electron withdrawing moieties, such as ester, acid,cyanide and anhydride. Preferably the enophile is an electrophillicalkene or alkyne. Even more preferably is selected from the groupconsisting of maleic anhydride, fumaric acid, itaconic anhydride,acrylic acid and maleate esters and most preferably it is selected fromthe group consisting of maleic anhydride and fumaric acid.

By non-mineral oil is meant oil, comprising triglycerides, that has beenobtained directly from plant or animal matter, including fish, ratherthan from a fossil feedstock.

Preferably, at least 80% by weight of the total triglycerides making upthe oil contain one or more double bonds, more preferably 85 to 100%,still more preferably 90 to 100%, yet more preferably 95 to 100% andmost preferably 100%. The amount of fully saturated triglycerides ispreferably kept as low as possible as such triglycerides are unreactiveto the enophile. The oily exudate seen on the surface of dried latex andpaint films is thought to be this unreacted saturated material.

Transesterifying the oil or mixture of oils tends to randomise the fattyacid portions of the triglycerides making up the oil. This is aconsequence of the fatty acid portions between and within triglyceridesbeing rearranged. This produces oils having new mixtures oftriglycerides and also allows the inevitable variation in thetriglyceride composition to be evened out.

Transesterification can be carried out with a single oil, resulting inrandomisation of the fatty acid composition of the triglycerides. Or itmay be performed with a mixture, comprising two or more oils. Carefulchoice of the oil mixture to be transesterified allows the triglyceridecomposition to be controlled.

An additional benefit of transesterification is that by blending oilsand transesterifying the resulting mixture, a more consistent feedstockcan be produced for further reaction according to the invention.

Optionally, the macromonomer is diluted with a suitable solvent,preferably one that is also a polymerisable monomer in a final step.This ensures that the macromonomer does not solidify on cooling downfrom the reaction temperature making it easier to handle. Suitable suchmonomers which are also effective solvents include 2-ethyl hexylacrylate, butyl acrylate and styrene.

Transesterification may be performed in the presence of a suitablecatalyst at about 60 to 80° C. for approximately half an hour. Suitablecatalysts include alkali metal alkoxides, in particular sodiummethoxide, sodium ethoxide, sodium isopropxide, sodium hydroxide,potassium hydroxide, sulphated zirconia, tungstated zirconia,hydrochloric acid, sulphuric acid, boron trifluoride, sodium ethylate,stannium hydroxide, potassium glycerolate, sodium methylate and lipases.Preferably, from 0.05 to 1.5% by weight of the catalyst is usedcalculated on the total amount of oil to be transesterified, morepreferably from 0.05 to 1.0%, still more preferably from 0.1 to 0.5% andmost preferably from 0.1 to 0.3%. Preferably, sodium methoxide is usedas this is easily removed following the reaction. When sodium methoxideis used as the catalyst it is preferred to dry the oil and/or oils priorto the transesterification step in order to prevent the hydrolysis ofthe sodium methoxide. Preferably, the oil used to manufacture themacromonomer is derived from such transesterified oils.

Plant oils are preferred as their production consumes carbon dioxiderather than producing it.

Preferably the iodine value of the oil is less than 200, more preferablybetween 30 and 200 as the initial colour of the polymer film derivedfrom it is less yellow. Even more preferably the iodine value is from 50to 200, yet more preferably between 70 and 170, and most preferably from100 to 160.

It is preferable to keep the proportion of oil having iodine valuegreater than 140 g/100 g of oil to less than 80%, more preferably lessthan 70% and most preferably less than 60% of the mixture calculated ona weight basis.

The proportion of the fatty acid component (of the triglycerides in theoil) having more than one double bond, is preferably less than 15%, morepreferably from 0.5 to 15%, even more preferably from 1 to 12%, stillmore preferably from 1 to 10% and yet more preferably from 2 to 10% andmost preferably from 5 to 10% by weight. It is such polyunsaturatedfatty acids, especially having conjugated double bonds, which produceyellowing in dried paint films.

Suitable oils for use in the invention include, Palm oil, Soya bean oil,Cotton seed oil, Kapok oil, Mustard oil, Olive oil, Peanut oil, Rapeseedoil, Sesame oil and hydroxyl functional Castor oil. Preferably the oilsfor use in the invention are selected from the group consisting of Palmoil, Soya bean oil, hydrogenated Soya bean oil-also known as Soya wax,Cotton seed oil, Kapok oil, Mustard oil, Olive oil, Peanut oil, Rapeseedoil, Sesame oil, Corn oil, Safflower oil, Sunflower oil and Tall oil.

They may be used alone or blended with others.

Palm oil, Safflower oil and Soya bean oil are especially useful oils inthe invention as the macromonomers derived from them followingtransesterification, have good balance of reactivity and resistance toyellowing, when formulated into a binder, especially a polymer latex,for use in a coating composition.

All vegetable oils are a complex mixture of species. Nevertheless,average molecular weights are generally quoted in the region of 800 to900 Daltons. Palm oil, for example is 848 Daltons.

Preferably, the moiety on the ethylenically unsaturated monomer,reactive with the acid, ester or anhydride moiety of the enophile is ahydroxyl, amino or epoxide. Even more preferably, there is only one suchmoiety on the monomer.

Preferably the ethylenically unsaturated monomer reactive with the acid,ester or anhydride moiety of the enophile is selected from the groupcomprising hydroxyethyl (meth)acrylate, hydroxyl propyl (meth)acrylate,hydroxyl iso propyl methacrylate, hydroxyl butyl (meth)acrylate, allylalcohol, glycerol methacrylate, glycidyl (meth)acrylate, allyl amine,tert-butyl aminoethyl methacrylate. More preferred are hydroxy ethylacrylate and hydroxyl ethyl methacrylate and most preferred is hydroxylethyl methacrylate.

The reaction of the ethylencially unsaturated monomer (step iv of theinvention) is preferably carried out in the presence of a polymerisationinhibitor in order to prevent the monomer from homopolymerising. Asuitable such inhibitor is phenothiazine.

Preferably the chain extender material comprises hydroxyl, amine,oxirane or isocyanate moieties. More preferably, it comprises at leasttwo moieties capable of reacting with the acid, ester or anhydridemoiety of the enophile. Nevertheless, it is possible that atrifunctional material is acceptable if one of the moieties is muchslower to react than the other two. For example, this is thought to bethe case when glycerol is used, where the secondary hydroxyl group isless reactive than the two primary hydroxyl groups. Preferably, thechain extender material is glycerol as it is readily obtained fromsustainable plant material.

The mole ratio of oil:enophile is preferably less than or equal to 1,more preferably from 0.3 to 1.0, even more preferably from 0.50 to 1.00,still more preferably from 0.55 to 0.75 and most preferably from 0.60 to0.70. The resulting excess of enophile helps to reduce the amount ofunreacted oil thereby limiting the tendency to produce exudate.

The mole ratio of oil:chain extender is preferably greater than 1.8,more preferably from 1.8 to 10.0, even more preferably from 2.0 to 7.5,still more preferably from 2.5 to 5 and most preferably from 3.0 to 3.5.

The mole ratio of unsaturated monomer:oil is preferably less than 1:1,more preferably it is between 0.25:1 and 1:1, even more preferably from0.3:1 to 0.9:1, yet more preferably from 0.5:1 and 0.85:1 and mostpreferably from 0.6:1 to 0.85:1. At these ratios, polymer films derivedfrom such macromonomers tend to be harder than films derived frommacromonomers of higher unsaturated monomer content. Furthermore, thelower level of unsaturated monomer relative to the oil results in anincreased content of renewable resource in the macromonomer and, thus,the final coating, which is environmentally beneficial. Finally, due tothe high energy content required to produce the ethylenicallyunsaturated monomer, a significant cost saving is also realised.

The mole ratio of oil:enophile:unsaturated monomer:chain extender ispreferably 1.00:1.50:0.75:0.30. Even more preferably the oil is Soyabean oil, the enophile is maleic anhydride, the unsaturated monomer ishydroxyl ethyl (meth)acrylate—most preferably hydroxyl ethylmethacrylate, and the chain extender is glycerol.

The reaction of the oil with the enophile is thought to produce anadduct of the triglycerides comprising the oil, and the enophile. Theadduct having an acid, ester or anhydride moiety reacts with a suitablefunctional moiety on the ethylenically unsaturated monomer to form anintermediate polymerisable triglyceride monomer. Further reaction with achain extender material, increases the molecular weight of theintermediate thereby ensuring that the proportion of triglyceride notfunctionalised with the unsaturated monomer iv) is kept to a minimum.This reduces the tendency for exudation from polymers comprising suchmonomers.

As the macromonomer is the product of an oil comprising a mixture oftriglycerides, some of which have a functionality greater than one, withother reactants also having functionality greater than one, themacromonomer is thought to be a complex mixture of species.

In practice, the reaction of the triglycerides with the enophile to formthe adduct is further complicated because the triglycerides (of the oil)themselves can have differing degrees of unsaturation (ie mono-, di- ortri-ene).

The degree of conjugation of any unsaturation greater than one; that isdi- and tri-enes, also affects the reaction mechanism by which theadduct is produced. For enes and unconjugated dienes, the preferredreaction is thought to be the Alder-ene reaction and for conjugateddienes, the preferred reaction is the Diels-Alder reaction.

FIGS. 1 and 2 show a simplified and idealised diagrammatic scheme forthe formation of one of the species that make up the macromonomer of theinvention. In this case the enophile is maleic anhydride; theunsaturated monomer is hydroxyl ethyl methacrylate and the chainextender is glycerol.

FIG. 1 shows a reaction scheme of a triglyceride (1) reacting withmaleic anhydride and hydroxyl ethyl methacrylate. The triglyceridecomprises a saturated fatty acid-palmitic acid, a mono-unsaturated fattyacid-oleic acid and an unconjugated diene fatty acid-linoleic acid. Inthe presence of sufficient iodine, any unconjugated diene becomesconjugated as shown in structure (2). This triglyceride comprising aconjugated diene fatty acid reacts with the maleic anhydride via theDiels-Alder reaction to form the adduct containing the cyclic hexenestructure depicted in (3). Furthermore, in some circumstances anynon-conjugated, unsaturated double bond will react with the maleicanhydride via the Alder-ene reaction. For simplicity, we show both themono-unsaturated and the diene reacted with the maleic anhydride on thesame triglyceride molecule. The extent to which this happens, if at all,will depend on the relative molar amounts of the enophile andtriglycerides of the oil; and the level of unsatuaration andconjugation.

It is thought that the adduct (3) reacts with the hydroxyl ethylmethacrylate to form a structure depicted as (4).

FIG. 2 shows the reaction of structure 4 with glycerol to form one ofthe species (5) of the macromonomer.

Preferably the molecular weight of the resulting macromonomer is atleast twice that of the triglyceride monomer.

The oil is represented by an idealised triglyceride structure (1)comprising palmitic acid, oleic acid and linoleic acid.

In a further aspect of the invention there is provided a polymerisableethylenically unsaturated macromonomer being the reaction product of

-   -   i) an adduct formed from the reaction of an unsaturated        non-mineral oil reacted with an enophile having an acid, ester        or anhydride moiety and    -   ii) an ethylenically unsaturated monomer having a moiety        reactive with the acid, ester or anhydride moiety of the        enophile and    -   iii) a chain extender material having at least two moieties        reactive with the acid, ester or anhydride moiety of the        enophile    -   wherein the unsaturated non-mineral oil is a mixture of        triglycerides produced by transesterification.

Preferably, the transesterification takes place above 50° C., morepreferably from 60 to 80° C. and most preferably about 70° C.

The reaction of step i) is preferably carried out above180° C., morepreferably from 200 to 300° C. and most preferably from 200 to 250° C.

Where the fatty acid component of the triglycerides comprising the oilcontains less than 30% of fatty acids having conjugated double bonds, itis preferred to heat the oil in the presence of iodine at a temperatureof from 80 to 150° C., more preferably from 80 to 120° C., even morepreferably from 90 to 110° C. and most preferably 100° C. The presenceof the iodine serves to convert the unconjugated double bonds, forexample of linoleic acid, to conjugated double bonds which are thus ableto react with the enophile and/or dienophile, for example maleicanhydride, via the preferred Diels Alder reaction. Preferably the ratioof iodine:oil is from 0.002:1 to 0.010:1 calculated on a molar basis. Ona weight basis this is equivalent to about 0.0006:1 to 0.003:1 dependingon the molecular weight of the oil. We have found that macromonomerproduced including this step produces less yellowing in a polymer bindercomprising the macromonomer than binder derived from macromonomerproduced without the iodine step. This is even more evident when suchbinders are used to make pastel or white paint.

Depending on the choice of unsaturated oil, the resultant neatmacromonomer can vary in appearance at room temperature from areasonably fluid liquid to a greasy or even waxy consistency. The oilsof low iodine value, say less than 100, tend to be soft solids sincethey are more saturated than the higher iodine value oils.

In a further aspect of the invention, there is provided an additionpolymer comprising the macromonomer as hereinbefore described.Preferably the macromonomer is polymerised with other ethylenicallyunsaturated monomers. Examples of suitable such ethylenicallyunsaturated monomers include (meth)acrylic acid esters, amides, andnitriles, vinyl monomers and vinyl esters.

It is preferred that the polymer comprises more than 6 wt % of themacromonomer of the invention, more preferably from 6 to 80 wt %, evenmore preferably from 15 to 75 wt % and most preferably from 20 to 60 wt%.

Using the nomenclature of (meth)acrylate to represent both acrylate andmethacrylate, examples of suitable other acrylic acid esters andmethacrylic acid esters are alkyl esters, preferably methyl(meth)acrylate, ethyl (meth)acrylate, propyl (meth)acrylate, butyl(meth)acrylate, 2-ethyl hexyl (meth)acrylate and alkoxypoly(oxyethylene) (meth)acrylate. Small amounts of methacrylic acidand/or acrylic acid may also be used. Hydroxy functional monomers suchas hydroxy ethyl (meth)acrylate and hydroxy isopropyl (meth)acrylate maybe included also. Examples of suitable vinyl monomers include styreneand alpha methyl styrene, vinyl propionate, vinyl butyrate, vinylacetate and vinyl versatate. Preferably the addition polymer is derivedfrom the esters of acrylic acid, methacrylic acid and optionally styreneand/or its derivatives. More preferably, the other monomers are styreneand 2-ethyl hexyl acrylate.

The glass transition temperature, or Tg, of the polymer comprising themacromonomer of the invention may be varied by copolymerising monomersof appropriate Tg. In this way copolymers which are hard, soft or ofintermediate Tg can be made, which can produce a wide range of physicalfilm properties such as tack (or stickiness), hardness andextensibility.

Preferably the Tg of the polymer is from −70 to 185° C., more preferablyfrom −20 to 120° C. More preferably the polymer is suitable for use as abinder in coatings especially in architectural coating compositions. Forsuch binder polymer dispersions the preferred range is from −20 to 120°C., yet more preferably from −15 to 60° C., even more preferably from−10 to 25° C. and most preferably from −10 to 10° C. as this produces amore durable paint which is better resistant to knocks and scuffs.

More preferably, the polymer is in the form of an aqueous compositionand still more preferably is an aqueous dispersion of polymermicroparticles. By aqueous is meant that at least 50% by weight of thecarrier liquid is water, more preferably more than 75% and mostpreferably the carrier liquid is water.

Preferably the polymer microparticles have a mean diameter of from 0.05to 2 microns, more preferably from 0.05 to 1.0 microns, still morepreferably from 0.05 to 1.0 microns and most preferably from 0.05 to 0.3microns.

Optionally, the microparticles are of the core-shell type having a corepolymer composition different from the shell polymer composition.Preferably, the core:shell ratio calculated on a weight basis is from1:8 to 2:1, more preferably from 1:2.

The ethylenically unsaturated monomers are caused to copolymerise byheating the monomer, in a carrier liquid-preferably water, containingpolymerisation initiators, preferably to a temperature of from 30° C. to150° C., preferably from 40° C. to 80° C. More preferably thepolymerisation process used is an aqueous emulsion polymerisationprocess. In such a case the maximum polymerisation temperature shouldnot exceed 98° C. Even more preferably, where redox initiatorcombinations are used, the preferred polymerisation temperature is from20° C. to 80° C. and most preferably from 30° C. to 70° C.

Suitable emulsion polymerisation initiators include oxidants, forexample, peroxides such as tertiary butyl hydroperoxide, hydrogenperoxide and cumene hydroperoxide; persulphates such as potassiumpersulphate and ammonium persulphate; azo types such as 4,4′ azobis(4-cyanopentanoic acid). Preferably from 0.002% by weight to 5% byweight of the initiator is used, calculated on the amount ofethylenically unsaturated monomers, more preferably from 0.05 to 2% andmost preferably from 0.1 to 1%.

Reductants may be used in combination with the oxidant to form so calledredox couples. This enables the polymerisation to be run at lowertemperature than when relying on thermal decomposition alone. Suitableexamples of such oxidants include sodium ascorbate, sodiummetabisulphite and sodium formaldehyde sulphoxylate. Suitable examplesof redox couples include tertiary butyl hydroperoxide with ascorbic acidor sodium ascorbate or sodium metabisulphite or sodium formaldehydesulphoxylate; hydrogen peroxide with ascorbic acid, sodium ascorbate orsodium metabisulphite or sodium formaldehyde sulphoxylate; cumenehydroperoxide with ascorbic acid sodium ascorbate or sodiummetabisulphite or sodium formaldehyde sulphoxylate. More preferred isthe redox couple tertiary butyl hydroperoxide with sodium ascorbate.

Optionally, metal salts such as copper, chromium and iron salts can beadded when redox pairs are used. Such metals, usually in the form ofwater soluble salts, for example iron(II) sulphate, are especiallyuseful where the natural level of dissolved metals in the reactionmixture are low. This can occur when a glass-lined reactor is used or ametal chelating agent is present. The presence of the added metal saltsensures that the redox system works effectively. Preferably the level ofadded metal salt is kept to a minimum to avoid discolouration of thedispersion itself and any coatings derived from it. This is generallyless of a problem for adhesives.

The preferred initiator system is the redox combination of tertiarybutyl hydroperoxide and ascorbic acid, the latter optionally in the formof sodium ascorbate. Such redox combinations allow the polymerisation tobe carried out or around ambient temperature such as from 30 to 55° C.

In a further aspect of the invention there is provided a process ofproducing an aqueous dispersion of polymer microparticles derived from amonomer mixture comprising the macromonomer and other ethylenicallyunsaturated monomers, as hereinbefore described.

Preferably the process comprises the steps of

-   -   i) making an emulsion of ethylenically unsaturated monomers        comprising the macromonomer and other monomers, in aqueous        medium, preferably water, containing surfactant    -   ii) charging from 5 to 25% by weight of the monomer emulsion to        a polymerisation vessel and causing it to polymerise to form        polymer microparticles of mean particle diameter of from 0.05 to        0.5 microns    -   iii) feeding the remaining monomer emulsion of step i) to the        vessel in the presence of the microparticles of step ii) and        causing it to polymerise and grow them to form the final        microparticles of mean particle diameter of from 0.05 to 2.0        microns.

More preferably, the process comprises the steps of

-   -   i) making an aqueous emulsion comprising the macromonomer and no        other monomer    -   ii) charging the emulsion to a polymerisation vessel and adding        at least some of a mixture of neat comonomers to the vessel and        causing the combination of comonomers and macromonomer to        polymerise to form polymer microparticles of mean particle        diameter of from 0.05 to 2 microns    -   iii) feeding a neat mixture of the remaining comonomers to the        vessel in the presence of the microparticles of step ii) and        causing it to polymerise and grow them to form the final        microparticles.

This has the advantage that there is no need to make an aqueous emulsionof the macromonomer and the other ethylenically unsaturated monomersthereby saving time. Furthermore, it ensures that the macromonomer ofthe invention is polymerised into the particles.

In a yet further aspect of the invention there is provided a coatingcomposition comprising the addition polymer as hereinbefore described.Preferably, the coating is aqueous. More preferably the coating is anarchitectural paint for use on the interior and exterior surfaces ofstructures such as found in homes, offices and gardens. Even morepreferably, the paint is of non-Newtonian rheology, even morepreferably, thixotropic rheology.

The coating composition may also contain ingredients selected from thegroup consisting pigments, fillers, waxes, extenders, rheologicalmodifiers, dispersants, anti-foams, plasticisers, crosslinking agents,flow aids and biocides.

Materials Used in the Examples

RD Palm Oil is available from Hampshire Commodities, Fleet, Hampshire,UK, GU51 3SR.

Sunflower oil is available from Kerfoot, The Olive House, Standard WayIndustrial Estate, North Allerton, North Yorkshire, England.

Agripure AP-660 (hydrogenated Soya bean oil-fatty acid compositionmainly stearic acid) available from Cargill Inc, North America

tert-butyl hydroperoxide (t-BHP) is available from Akzo-Nobel

Disponil A4066 is available from Henkel

Tests

Molecular weight was determined by Gel Permeation Chromatography (GPC)using a Waters 150 CV fitted with a refractive index detector. Thecolumns used were 2×30 cm PLGel Mix D GPC columns at a temperature of35° C. Polystyrene (ex. Polymer Laboratories) was used as the standard.The test material was dissolved in tetrahydrofuran at a concentration of1 mg cm⁻³. The flow rate was 1 cm³ min⁻¹.

Examples of the invention will now be described.

Transesterified Oil-TO 1

A mixture of 360 g of Sunflower oil and 240 g of hydrogenated Soya waxwas heated to 80° C. in a rotary evaporator flask under a vacuum of 9mbar for 30 minutes.

The dried oil was transferred from the evaporator to a 3-necked, 1 litreround bottomed flask fitted with a water condenser, a stirrer and sourceof nitrogen. The mixture was heated to 70° C. under a nitrogen blanketand once on temperature 1.2 g of sodium methoxide was added and thereaction allowed to proceed for 30 minutes. After this time 6 g ofdeionised water was added to the flask and stirred for 5 minutes,following which 2 g of Kieselguhr filter aid was added. The resultingmixture was passed at 70° C. through a fine glass filter funnel. Thestarting and final oil mixture had the following mixture oftriglyceride.

Table 1 shows the fatty acid composition of the triglycerides making upthe starting sunflower oil and hydrogenated soya bean oil and the finaltransesterified mixture of TO 1 and TO 2. The composition was determinedusing Matrix Assisted Laser Desorption/Ionisation-Time of Flight(MALDI-TOF).

TABLE 1 Hydroge- Transesterified Transesterified Triglyceride Sunflowernated Soya oil TO 1 oil TO 2 composition oil Bean oil 60:40^(#)70:30^(#) OOO 5.7 0 12.9 8.3 LOO 14.9 0 18.3 16.2 LLO 27.3 0 7.2 17.5LLL 25.4 0 5.9 15.7 LLLe 0.2 0 0 0 LLeLe 0 0 0.1 0 OOP 2.1 0 7.5 5.1 LOP5.3 0 3.7 4.4 LLP 9.0 0 4.8 7.1 LLeP 0.4 0 0 0 LeLeP 0 0 0 0 OOS 1.1 0.114.6 12.2 OSP 0.2 0 2.7 1.8 OSS 0 0.3 5.1 3.7 OPP 0.2 0 0.5 0.3 LPP 0.90 1.1 1.0 SSS 0 59.9 2.8 1.9 PPP 0 0.5 0.2 0.2 SSP 0 30.5 2.0 1.7 SPP 04.8 0.7 0.5 Mono and 7.3 3.9 9.9 disubstituted glycerides Saturated 0 0Unsaturated 92.7 84.4 (total) Unsaturated 83.4 41.0 (>1) ^(#)startingweight ratio of sunflower oil to hydrogenated soya bean oil O representsoleic acid L represents linoleic acid Le represents linolenic acid Prepresents palmitic acid S represents stearic acid

OOO indicates the triglyceride having three oleic acid groups; OSPrepresents the triglyceride having oleic acid, stearic acid and palmiticacid.

MALDI-TOF analysis of the Interesterified oil 1 shows that thetriglycerides having more than one ethylenic unsaturation reduces fromapproximately 83% to 41% by weight.

MACROMONOMER EXAMPLE MM 1

The macromonomer MM 1 was prepared according to the method describedbelow and using the ingredients listed.

g Transesterified oil TO 1 450.00 Maleic anhydride 78.59 Iodine 0.69Phenothiazine 1.98 Hydroxy ethyl methacrylate 52.56 Glycerol 13.48

450gms of the transesterified oil together with 78.59 gms of maleicanhydride and a few drops of xylene where charged to a 1000 ml 3-neckedround bottomed flask. Also fitted to the flask was a nitrogen inletdesigned to give a slight positive pressure to the system in order tomaintain a nitrogen blanket. A thermocouple, mechanical stirrer andcondenser were also fitted to the flask. The reactor contents wereheated under stirring at 150 rpm to 100° C. at which point 0.69 g solidiodine was added. The reaction was stirred at 100° C. for 10 minutesafter which the temperature was increased to 200° C. Once at 200° C. thereaction was maintained at this temperature for 30 minutes. After thistime the reaction temperature was increased to 220° C. and held therefor 4 hours after which it was cooled back to 200° C. Once at 200° C.,1.98 gms of phenothiazine was added. This was allowed to mix for 5minutes after which 52.56 gms of 2-hydroxyethyl methacrylate (HEMA) wasadded from a dropping funnel over a 30 minute period. After the HEMAaddition had been completed the reaction was held at 200 C for 60minutes. After the 60 minute hold 13.48 gms of glycerol (pre-warmed to50° C.) was added to the reaction in a single shot. The reaction wasagain held at 200° C. for a period of 60 minutes. The reaction was thenallowed to cool to 50° C. at which point the resultant macromonomer waspoured into 2×500 ml jars containing a small quantity of molecularsieve.

Transesterified Oil TO 2

A mixture of Sunflower oil and hydrogenated Soya wax was transesterifiedaccording to the method of TO 1. The only difference was the weightratio of the Sunflower oil to Soya wax was 70:30.

The triglyceride composition is shown in Table 1.

MACROMONOMER EXAMPLE MM 2

The macromonomer MM 2 was prepared according to the method describedbelow and using the ingredients listed.

g wt % Transesterified oil TO 2 152.400 75.971 Maleic anhydride 25.59012.757 Iodine 0.223 0.111 Phenothiazine 0.300 0.150 Hydroxy ethylmethacrylate 16.981 8.465 Glycerol 4.806 2.396 Hydroquinone 0.300 0.150

To a 700 ml round bottomed flask fitted with a water cooled condenser,means to provide a nitrogen blanket and an anchor stirrer operating at75 rpm was added the 152.400 g interesterified oil and 25.590 g maleicanhydride. The mixture was heated to 100° C. and 0.223 g iodine wasadded. The temperature was raised to 200° C. and held there for 30minutes and then increased to 220° C. After 5 hours and thirty minutesit was cooled to room temperature. The resulting mixture described abovewas heated to 100° C. and 0.300 g phenothiazine was added. The mixturewas then heated to 200° C. and the 16.981 g Hydroxyethylmethacrylate wasfed in via a dropping funnel over 15 minutes. The mixture was held for 1hour at 200° C. 4.806 g glycerol was added as a shot and then themixture held for 1 hour to give the final macromonomer. The macromonomerwas then cooled back to approximately 170° C. and 0.300 g hydroquinoneadded. Cooling was continued to approximately 70° C. and themacromonomer was filtered through lambswool.

LATEX EXAMPLE Latex 1

A latex was made using the following ingredients and procedure

g wt % Prefeed reductant shot Sodium Ascorbate/1 0.416 0.038 DeminWater/1 1.651 0.150 Monomer Premix MM 2 122.959 11.178 Styrene 248.54522.595 2-ethyl hexyl acrylate 120.332 10.939 Ammonia (25% solution)7.659 0.696 Surfactant solution Demin water/2 521.510 47.410 DisponilA4066 41.285 3.753 Initiator Solution Tertiary butyl hydroperoxide 5.2270.475 Demin Water/3 9.531 0.866 Reductant Solution 1 Demin water/4 9.5310.866 Sodium ascorbate/2 0.832 0.076 Reductant Solution 2 Demin water/59.531 0.866 Sodium ascorbate/3 0.988 0.090

Prepare 931.672 g of Monomer Pre-emulsion by mixing the indicatedweights of macromonomer MM 1, styrene, 2-EHA and adding the ammoniaunder gentle stirring for about 10 minutes, adding the ammonia dropwise.Add this monomer mixture to the surfactant solution of 521.51 g ofDemin/1 and 41.285 g Disponil A4066 under high shear mixing conditionsusing a Silverson homogeniser to form an emulsion of monomer in wateruntil the mean droplet size is about 150 nm and there are no monomerdroplets greater than 2000 nm. This will require about 20 minutes.

Prepare the prefeed reductant shot by dissolving the sodium ascorbate inwater.

Prepare the reductant solutions by dissolving the sodium ascorbate inwater

Prepare the initiatior solution by dissolving tertiary butylhydroperoxide in water.

To a 2 L parallel sided vessel fitted with a propeller stirrer,condenser and a nitrogen blanket, add 37.567% of the MonomerPre-emulsion and raise the temperature to 50° C. and add prefeedreductant shot. After 5 minutes at this temperature add 5% of theinitiator solution. Hold for 5 minutes and then feed the remainder ofthe Monomer Pre-emulsion linearly over 90 minutes whilst concurrentlyfeeding Reductant solution 1 over 90 minutes and 85% of initiatorsolution over 90 minutes. Hold at 50° C. for a further 15 minutes andthen add 10% of the initiator solution and hold for 5 minutes. Addreductant solution 2 linearly over 30 minutes. Maintain at 50° C. for 15minutes and then cool and filter through 80 mesh nylon.

There was very little build-up on the reactor walls or the stirrer andthe latex was bit free.

The latex constants were

pH: 7.4

weight solids: 47.0%

Rotothinner- 0.6 poise @ 25° C.

MFFT was 3.6° C.

PAINT EXAMPLE Paint 1

A semi-gloss paint was made using Latex 1 and the ingredients listedbelow.

Mill Base Stage

Load to a Clean Dispersion Vessel

Tap water 10.404 Texanol 1.200 Orotan 731 A 1.850 Dispelair CF 823 0.173

Start disperser on low speed and begin adding pigmentation.

Increase speed as millbase thickens to maintain a good vortex.

China clay supreme 6.000 Tioxide TR92 18.240 Microdol H600 6.000

Run 20 minutes. Check dispersion is less than 20μ.

Then add the other materials adjusting speed as required.

Dispelair CF823 0.173 Product V189 0.020 Tap water 3.000 Aquaflow NHS300 0.750 Acrysol SCT-275 0.750 SUB-TOTAL 48.560

Run 10 minutes

Cover and allow mill base to cool before making into finished product.

Paint Stage

Load mill base to a clean vessel

Mill base 48.560 Add with stirring Latex 1 50.100

Pre blend

Run 10 minutes Adjust to viscosity with

Tap water 1.340 TOTAL 100.000

Paint Evaluation

The following tests were carried out on Paint 1

Viscosity

13.8 poise measured at 25° C. using a Rotothinner operating at 562 rpm.

Cone and plate: 1.6 poise @ 25° C.

pH 7.8

1. A method of making a polymerisable ethylenically unsaturatedmacromonomer comprising the steps of i) providing a chosen unsaturatednon-mineral oil or a mixture of unsaturated non-mineral oils having afirst blend of triglycerides; ii) treating the chosen unsaturatednon-mineral oil or mixture of unsaturated non-mineral oils with atransesterification catalyst to produce a second blend of triglyceridesdifferent from the first blend; iii) reacting the second blend oftriglycerides with an enophile having an acid, ester or anhydride moietyto form an adduct; iv) reacting the adduct with an ethylenicallyunsaturated monomer having a moiety reactive with the acid, ester oranhydride moiety of the enophile to form an intermediate; v) reactingthe intermediate of step iv) with a chain extender having at least twomoieties reactive with the acid, ester or anhydride moiety of theenophile to form the ethylenically unsaturated macromonomer.
 2. Themethod according to claim 1 wherein the second blend of triglycerideshas an iodine value between 30 and
 200. 3. The method according to claim1 wherein the mixture of unsaturated non-mineral oils is obtained fromplant matter.
 4. The method according to claim 1 wherein the mixture ofunsaturated non-mineral oils contains at least one oil selected from thegroup consisting of palm oil, sunflower oil, safflower oil, soya beanoil and hydrogenated soya bean oil.
 5. The method according to claim 1wherein the enophile is selected from the group consisting of maleicanhydride, itaconic anhydride, fumaric acid, acrylic acid and maleateesters.
 6. The method according to claim 1 wherein the ethylenicallyunsaturated monomer reactive with the acid, ester or anhydride of theenophile is selected from the group consisting of hydroxyl ethyl(meth)acrylate, hydroxyl propyl (meth)acrylate, hydroxyl iso propylmethacrylate, hydroxyl butyl methacrylate, allyl alcohol, glycerolmethacrylate, glycidyl (meth)acrylate, allyl amine, and tert-butylaminoethyl methacrylate.
 7. The method according to claim 1 wherein thechain extender is glycerol.
 8. The method according to claim 1 whereinthe molar ratio of non-mineral oil(s):enophile:unsaturated monomer:chainextender is 1:1.5:0.75:0.30.
 9. An ethylenically unsaturatedmacromonomer being the reaction product of i) an adduct formed from thereaction of an unsaturated non-mineral oil reacted with an enophilehaving an acid, ester or anhydride moiety; and ii) an ethylenicallyunsaturated monomer having a moiety reactive with the acid, ester oranhydride moiety of the enophile; and iii) a chain extender materialhaving at least two moieties reactive with the acid, ester or anhydridemoiety of the enophile; wherein the unsaturated non-mineral oil is amixture of triglycerides produced by transesterification.
 10. Anethylenically unsaturated macromonomer made by the process of claim 1.11. The ethylenically unsaturated macromonomer according to claim 10wherein the macromonomer has a weight average molecular weight, Mw, offrom 1000 to 50000 Daltons.
 12. An addition polymer derived from amonomer mixture comprising the ethylenically unsaturated macromonomeraccording to claim
 9. 13. The addition polymer according to claim 12wherein the polymer is in the form of an aqueous dispersion of polymermicroparticles.
 14. The addition polymer according to claim 13 whereinthe microparticles have a mean average diameter of from 0.05 microns to2.00 microns.
 15. The addition polymer according to claim 13 wherein theTg of the polymer is from −20 to 120° C.
 16. A coating compositioncomprising the addition polymer of claim
 13. 17. The coating compositionaccording to claim 16, further comprising an ingredient selected fromthe group consisting of pigments, fillers, waxes, extenders, rheologicalmodifiers, dispersants, anti-foams, tackifiers, plasticisers, flow aidsand biocides.
 18. The method according to claim 2 wherein the mixture ofunsaturated non-mineral oils is obtained from plant matter.
 19. Themethod according to claim 3 wherein the mixture of unsaturatednon-mineral oils contains at least one oil selected from the groupconsisting of palm oil, sunflower oil, safflower oil, soya bean oil andhydrogenated soya bean oil.
 20. The method according to claim 5 whereinthe ethylenically unsaturated monomer reactive with the acid, ester oranhydride of the enophile is selected from the group consisting ofhydroxyl ethyl (meth)acrylate, hydroxyl propyl (meth)acrylate, hydroxyliso propyl methacrylate, hydroxyl butyl methacrylate, allyl alcohol,glycerol methacrylate, glycidyl (meth)acrylate, allyl amine, andtert-butyl aminoethyl methacrylate.